Copyright © 2008 The Extensible Markup Language (XML) is a subset of SGML that is completely described in this document.
Please report errors in this document to the public [email protected] list; public archives are available.characters with both precomposed and base diacritic forms) match only if they have the same representation in both strings. (Of strings and rules in the grammar:) A string matches a grammatical production if it belongs to the language generated by that production.(Of content and content models:) An element matches its declaration when it conforms in the fashion described in the constraint [VC: Element Valid].] [Definition: Marks a sentence describing a non-binding recommendation included to increase the chances that XML documents can be processed by the existing installed base of SGML processors which predate the Web SGML Adaptations Annex to ISO 8879.] [Definition: A data object is an XML document if it is well-formed, as defined in this specification.The errata list for this fifth edition is available at A Test Suite is maintained to help assessing conformance to this specification.This document has been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and is endorsed by the Director as a W3C Recommendation.It is a stable document and may be used as reference material or cited from another document.W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment.Markup encodes a description of the document's storage layout and logical structure.XML provides a mechanism to impose constraints on the storage layout and logical structure.XML has been designed for ease of implementation and for interoperability with both SGML and HTML.This section describes the status of this document at the time of its publication. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at